


Respire

by avianbrother



Category: Apex Legends (Video Games)
Genre: Age Difference, Chronic Illness, Creampie, F/M, Smut, Soft Caustic, lab partners to lovers
Language: English
Status: Completed
Published: 2020-04-15
Updated: 2020-04-15
Packaged: 2021-03-01 18:20:57
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,684
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23661460
Author URL: https://archiveofourown.org/users/avianbrother/pseuds/avianbrother
Summary: It's hard to find good help--especially for someone like Caustic. When he asked for a lab assistant, all he got was weak little ol' you.Every time he sees you, it gets a little harder and harder to breathe.
Relationships: Caustic | Alexander Nox/Reader
Comments: 3
Kudos: 134





	Respire

**Author's Note:**

> I wrote this in October and let it sit in my files with every intention of rewriting and adding more, but fuck that we need all the horny content we can get right now.
> 
> Shout out to my waifu Wolfy on the discord server, who fuels 90% of my Caustic related ramblings.

You weren’t much of a lab assistant; small and a little too asthmatic to be useful at any of the highly competitive Frontier corporations, but you were the best the Apex game runners could offer to (presumed dead and wanted criminal) Alexander Nox.

When you had shuffled in the first day, timid and wearing your disposable face mask, you were certain he’d turn you away in disgust or even kill you. But he didn’t. Instead he’d stared at you for a few moments before setting you to work, instructing you on his preferred lab setup and how to clean the equipment. Back then you had assumed he felt nothing for you, that it was merely the beginning of your service under him. You were oh so very wrong.

***

Four months, the calendar said. It had been four months since you started assisting Caustic, though it felt so much longer than that to him. Rarely did he seek companionship, though he found yours…tolerable. _More_ than tolerable, in fact. Your presence in his makeshift lab was comforting, and lately he’d return to his quarters and be left… _wanting_.

It had started out innocent enough. The game coordinators weren’t complete imbeciles, they were aware who he was—who he had been—and they couldn’t afford to send a bright, healthy mind to be potentially murdered. And they had told him as much, warned that you were all they could give him if he wanted someone who valued their life over exposing any dirty secrets. He expected to be disappointed. He hadn’t expected the clenching around his heart at the sight of you, innocent and eager to please and fr—

No, you weren’t frail, he reminded himself. You were a hard worker, evident in the way you kept the lab pristine and flawlessly logged data, and how you followed command efficiently and quietly and with little complaint despite your own physical challenges. Admirable qualities that had allowed you to, slowly but surely, fall into his good graces without either of you realizing it. Once your diligence captured his attention, he began noticing your physical features as well. The brightness in your eyes, the curve of your hips, your laugh, your hair, your smile, all of it compounding his interest in you until he was wondering what you looked like beneath the lab coat and layers, and what you might look like beneath him.

(And only _he_ could feel no remorse over gassing living subjects yet feel ashamed for lusting after a pretty young thing like you).

Caustic looked from the calendar to the clock. You would be coming back with lunch soon. He stood from his place at the computers and stretched, his old bones crackling in protest. Research could wait, he decided. Once outside, the lab doors hissed shut behind him and he took off his gloves, mask, and apron.

“Caustic!” you called from down the hall, waving a couple paper bags in your hand.

Ah, right on time. He nodded in greeting and went to the little storage room the two of you had converted into a break room of sorts, though it was nothing more than a table and chairs, a couch, and a fridge to keep snacks. He tossed his gear on a storage rack and settled in his chair. You beamed under your mask as you passed him his lunch.

“Good news!” you said, voice slightly muffled. “I snuck us some extra chips and those pastries you like when the cashier wasn’t looking.”

“How devious,” he said, tone bland but with a slight quirk of his lips that told you he was amused.

From your own bag you pulled out a thermos filled with green tea and honey, a mixture to help soothe coughs. It had been a good day for the both of you so far; some days you drained the bottle dry and some days he swallowed his pride and drank some too to ease his throat and keep the coughing fits at bay. He never asked about your condition, just as you never asked about his. A silent understanding, where the only thing that mattered was whether it was a good day or a bad day.

“You’re wearing the masks I bought,” he noted, taking a bite of his sandwich. You blushed and looked away as you removed it so you could eat.

In a fit of madness (or affection), he had bought a set of disposable masks for you to keep around the lab. They came in an assortment of different styles, some stamped with cartoony mouths while others were decorated in colorful patterns. A rather juvenile choice to be sure, but one he thought you would enjoy. And judging by the design you were wearing, a kitty mouth with whiskers, it had been an excellent choice.

“They’re really cute,” you mumbled, picking at your food. “I’ve gotten a lot of compliments on them.” You gave him a shy smile that shot him in the heart.

His mouth went dry. A thousand different comments swirled in his head, ones that he could’ve passed off as smooth and flirtatious in his younger years but seemed far too stale coming from him now. “I’m glad you like them,” he said instead, in what he imagined was a steady voice. “Good to know I still have some sense of taste.”

You snorted. “I don’t know, you got a pretty good look going on for you. Like a…what did Gibraltar call it? Bear?” That got an amused huff from him. “Yeah, like a sexy mad scientist bear.”

It took you a minute to realize what had slipped out, to notice that Caustic had stopped eating and was now staring at you. Suddenly the room was uncomfortably warm. His expression was unreadable. Oh god, you took it too far, didn’t you? You had spent too much time in the company of bored STEM students whose version of entertainment was drawing dicks on whiteboards, and now you’d gone and said something stupid and your dumb ass was gonna get fired. Or worse, he’d never look at you again and force you to work in awkward silence and embarrassment for the rest of your life.

“I-I, u-uh…” You wished you were still wearing your mask, if only so you could hide your shame.

“It’s alright,” he said, in a tone that could’ve been interpreted as casual but was way too clipped for your liking. He continued eating as if the conversation had never happened, leaving you painfully tense until you finally decided to follow his lead and munched on your chips despite the pit in your stomach.

***

Normally you enjoyed the quiet in the lab, broken only by the steady hum of the ventilation and the computers. But now? Now it was a deathtrap. Caustic hadn’t spoken since lunch, and that was several hours ago. You didn’t have any battle instincts to speak of but even you could tell something dangerous was brewing under the façade of normalcy. It was worse than the time you bumped into him and accidentally broke a glass. At least then you had picked up the palpable frustration and disappointment rolling off of him.

You anxiously watched the computer run diagnostics on his traps, making sure the deployment mechanisms were fully operational. You jiggled your leg and checked over your shoulder. He was still watching video footage of the last match, taking notes. Your throat tightened and you suppressed the urge to wheeze and cough, as if any noise you made would set him off.

You’d always preferred older men, a preference that you kept to yourself because voicing it was just asking for trouble. After the initial nerves of being assigned to him wore off, you found that Caustic was…well, not all that bad to be around. He didn’t talk too much and when he did, he was polite to you and cracked terrible jokes with a straight face and traded stories of his college days. He had a fondness for cats and mugs with chemistry puns. He was a tree of man, beaten only be Gibraltar, and he made you feel small yet strangely safe. And he didn’t…didn’t question why some sickly bastard like you was a lab tech. He _understood_ , damn it. And if that was low fucking standards, then so be it.

Hopefully he didn’t think you were some filthy science harlot looking to screw your way up the ladder. Even if you didn’t have his affection, you had his respect and you wanted to keep that.

At some point the diagnostics finished and it let out a beep signaling it was ready. You undocked the traps and packed them away in an air-tight crate where they would wait until the next match. There wasn’t much left for you to do, all your other tasks completed. Hesitation kept you frozen in place for what felt like hours before you approached him.

“Caustic, sir?”

“Yes?” His arms were crossed in front of his chest and his eyes never left his screen. You winced.

“I did everything you told me to. Was there anything else you wanted before I left for the day?”

He let a noncommittal hum, barely glancing in your direction. You took that as your cue to leave. You headed for the door.

“ _You_.”

You stopped, hand hovering over the handle.

“W-what?” You turned and saw him standing there, the video paused.

“Come here. Please,” he said softly, the ever-present frown lines and furrow in his brow gone from his face, his expression one of vulnerability and confusion.

You couldn’t help but obey, meeting him with your own look of confusion and trepidation. His hands clenched and unclenched at his sides as he focused on some distant point, unable to look you in the eye.

“What do you think of me?” he asked after a while. You bit your lip, thankful for the thin barrier of your mask to hide your anxiety.

“I think you’re a brilliant man,” you answered. “You’re one of the best Legends the arena has ever seen, your work is—”

He sighed and shook his head. “No, what do you think of _me_?”

Your heart hammered in your chest, so loud he surely heard it too. Swallowing thickly, you said, “I think you’re very attractive, sir…and I would like to get to know you better, outside work. You make me feel…safe and valued and special.”

There was a sharp intake of breath, and he studied you from under his goggles before he stepped closer and said, “So I can assume you’d be very happy to know that the feelings are mutual.”

You nodded, warmth blossoming in your chest. He slid off his gas mask and set it on the table beside him, then hooked a finger in your mask, slowly pulling it down to reveal your lips. There was a split second of hesitation before he dove in, cradling your chin in one hand as he pressed his lips to yours. You whimpered, hands coming up to grab fistfuls of his apron while you tried desperately to ground yourself. Your lips parted and, in a moment of bravery, you slid your tongue into his mouth, probing and tasting, dominating the kiss. He released your chin and wound his fingers in your hair, guiding you as he kissed back with equal fervor. He tasted of tea and salt, and his beard scrubbed against your cheeks.

When your lungs started burning, you finally parted for air. The two of you locked eyes, and it became quite clear you both wanted the same thing. A knot of arousal coiled in your gut as he took you by the hand and lead you out the lab and across the hall to the break room. He kicked the door shut behind you and shoved you onto the couch, bracing his arms on either side of your head as he kissed you once more, firmly, insistently, like you would disappear if he didn’t. He straightened up and started stripping, tossing his clothes to the floor without a care. After a second you followed suit, hands trembling because _oh god, this was really happening_. Whether he was impatient or maybe a little self-conscious, you weren’t sure, but he didn’t bother stripping his pants and seemed content with simply pulling out his cock, already hard and leaking pre. You paused with your panties halfway down your thighs, ass hanging out. He raised a brow, looking at you expectantly. You let them drop and undid your bra, tossing it aside.

He lazily stroked himself, giving you an eyeful as he eyed you in return. He wasn’t a monster, but you still clenched at the sight of his cock, wondering how it would fit.

“It’s…it’s been a while,” you said. The hunger in his eyes softened, and he gently pet your head. You were everything he had hoped for—soft where he liked it and hard where it mattered—and he would give you all the prep and care you wanted if it meant having you for a single moment.

“I’ll try to be gentle,” he said, dropping to his knees. He parted your legs and grabbed you by the hips, bringing your folds to his face. He didn’t think either of you had the stamina or breath for too much oral, but for you? He’d eat your pussy ‘til you choked him with your thighs.

The first brush of his tongue had you gasping, holding onto the cheap material of the couch like a life preserver. His beard alternated between tickling and chaffing as he buried his tongue in your heat, savoring the taste of you and nudging you to grind on his face. You whimpered and squirmed, one hand coming up to wind in his dark locks and guide him towards your clit. Caustic wasn’t an obedient man, but there are some things a man should never argue. And if a girl wants you to suck her clit? _You suck her fucking clit_.

Perhaps he went a bit hard but the way you keened was music to his ears. You yanked his hair and he eased the pressure, switching to broad licks while he maneuvered you and gingerly worked a finger inside you. You moaned and tipped your head back, enjoying the pleasant stretch. He probed around, searching for that spongey spot he knew would be right…

“There! Right there!” you gasped. He couldn’t help a smug grin. He was rusty but he still had it.

He added a second finger, rubbing your g-spot while he mouthed your clit. Then he added a third when your cries began to die down, scissoring and stretching you open. Jolts of pleasure arced across your body, making you tense and relax, tense and relax, twisting in his grasp as your legs twitched. That familiar precipice was approaching, and you knew you weren’t going to last. The final push came when he sucked on your clit the same time he pressed against your g-spot, and you absolutely _snapped_. You didn’t have it in you to scream but you whined and let out broken, choked cries as you came on his tongue and clenched around the same hand he used to end countless lives in the arena.

Your throat was tight. Your heart was pounding. Oh fuck, _breathe_ , you reminded yourself. You were vaguely aware that your thighs weren’t on his shoulders anymore, and you gathered enough strength to prop yourself up and look at him. Slick glistened on his lips and beard, and he had a hand on your chest, head tilted in concern. There was a faint rasping sound that you realized was coming from you.

“Are you alright?” he asked. You cracked a smile, still riding the faint waves of your high.

“Yeah, yeah I’m good,” you wheezed, taking a second to cough and clear your throat. You laughed and patted his hand. “I can’t believe it, but you _literally_ took my breath away.”

He was stunned. Then he let out his own deep, crackling chuckle.

You closed your eyes and laid there to recover, though he didn’t give you long. His hands wandered and squeezed your breasts, turning your pleasured hums into a moan as he thumbed your nipples.

Now that he wasn’t focused on your needs, his own pressing desire was calling for attention. He had spent enough time on foreplay, he concluded as he grabbed you and manhandled you into position. The sudden change in pace and mood had you flushed and nervous again. He laid you on your back, bringing one leg around his waist and draping the other over his shoulder.

“It’s Alexander, by the way,” he said. “Or Alex, if you can’t manage.”

“W-what?”

He stopped and stared, giving the meat of your thighs a firm, delicious squeeze. “That’s my name. So you can scream it when I make you cum a second time.”

“O-oh—”

He shoved himself in without fanfare. Even with prep, it was a stretch, one that left you aching and digging your nails into the couch with a hiss. You opened your eyes—when had you shut them? —and blinked up at him. He met your gaze, rubbing circles into your thigh with a thumb. He needed time to adjust as well, the tightness of your pussy almost painful and overwhelming. When he finally started moving, he began with slow, rocking thrusts. Barely pulling out before easing back in. In and out, in and out, until you went slack and relaxed against the cushions, hips rising ever so slightly to meet his thrusts. At some point he hit the right spot, a light gush of slick flowing out as your eyes widened, and he decided to go to fucking town.

Each thrust seemed to hit deeper than the last and drive you into the cushions. The only thing keeping you in place was his firm grip and his determination to fuck you raw. His brow furrowed in concentration as he focused on brushing your g-spot with every pass, taking pride in the way your tits bounced and your face contorted in pleasure, little whimpers and sobs eking out. He kept going until you reached the edge, driving into you even as you cried and came, walls fluttering around his cock from the overstimulation.

It felt good, goddamn, it was _good_. But you wanted more.

You reached out, running your hand across his hair-covered chest. He slowed, letting go of one leg in favor of keeping your hand pressed there, right over the frantic beat of his heart.

“Alex?” you asked, breathy and so, so desperate.

“What do you need?” He punctuated his question with a sharp thrust that made you whine.

“I wanna touch you, _please._ ”

You didn’t have to ask twice. Caustic brought your other leg around his waist too, pulling you close so he covered you with his bulky frame. You nuzzled your face in his neck, arms around his shoulders to keep you anchored. He felt warm, safe, even if the weight and heat made it that much harder to breathe. He wound a hand in your hair and pulled you in for a kiss, light but loving. You angled your hips and _oh_ , when he started up again, drowning you in throbbing, steady satisfaction.

You lost track of how long you were like that, arching under him and greedily taking every inch of what he had to give. But all good things must come to an end, and his thrusts started to get sloppy as he neared his own release.

“Can I cum in you?” he rasped. You nodded weakly, spurring him on with a squeeze of your legs. He growled and held you tight, cursing as he finished inside you.

He slumped, barely catching himself with the last dredges of his stamina before he could crush you beneath him. Both of you groaned when he pulled out; the sudden emptiness left you feeling hollow. You ignored the sticky mess in your hole, choosing instead to sit up and lean against your boss-turned-lover. A comfortable silence fell over you. Your limbs were shaky, and you felt thoroughly destroyed.

It was probably late, you realized, returning to your surroundings. You were tired. You almost wanted to fall asleep right there, naked and leaning your head on Caustic (or was it Alexander now?), but knowing your luck and immune system, you’d get yourself sick.

“So…” you started.

“So…?” he echoed.

“So, are we, you know—” you gestured vaguely between the two of you, “—a thing?”

He sighed, just as sated and exhausted as you. “I should hope. Unless my performance somehow proved unsatisfactory.” There was a hesitance, a hint of self-consciousness, you would have never noticed two or three months ago. You loosely linked your hand with one of his, the size difference so very clear after what had just occurred, and sloppily kissed the shoulder you were leaning on.

“No, the performance…was _very_ satisfactory,” you said airily. “But I don’t think they’ll be very happy about the ‘fucking my boss’ part of this.”

He scoffed. “Our relations are the least of their concerns.” He nudged you off and stood, tucking his cock back in his pants and gathering his clothes. He tossed you yours as well, not quite ogling anymore but still admiring your form while you dressed.

Once you were decent, the two of you stood there, awkwardly exchanging glances before he coughed into his fist and said, “If you are still open to the suggestion, would you like to meet at a café and get to know each other better?”

You blushed. Even though he had just fucked you on the breakroom couch, it was such an innocent suggestion that had you flustered. “That would be nice, actually.”

Caustic smiled and stepped out, waiting until you had followed after before shutting the door. He didn’t offer his hand, nor did he put an arm around your waist, but he walked side-by-side with you down the hall, in silent understanding.

**Author's Note:**

> People have pointed out that some of Caustic's coughing and other issues are indicative of him having CF, and I'm wholly on board with this headcanon. What the reader suffers from is open to your interpretation.


End file.
